Conventionally, the method for manufacturing electrical wire utilizes an extrusion manufacturing process to extrude an opaque plastic material uniformly onto the surface of a plurality of electrical wires, each of the wires surrounded with an insulating medium, to form a uniform outer protection layer with better insulation. As to the method for manufacturing colored wire, it is merely by adding dye into the plastic material in the process to produce the color wanted. The color obtained by utilizing the conventional technique is monotonous or irregular, which is unable to let the wire present a variety sparkling color.
As to those conventional wires used for manufacturing handicraft or other decorative articles, they are generally classified as soft wire and hard wire depending on their hardness. Typically, soft wire is formed of stranded color filaments by using a conventional manufacturing process, which is tedious and labor consuming. This kind of soft wire is easy to be dirtied, but not easy to be cleaned, and the color thereof will easily fade away. Moreover, the soft wire is limited in applications since there is no support member, such as rigid metal or non-metal material, being inserted in the wire. Hence, wire manufacturers in the art implemented the conventional method as stated above to manufacture the wire having a metal or non-metal support member therein by utilizing an extrusion manufacturing process to extrude an opaque plastic material uniformly onto the surface of the metal or non-metal support member. As a result, the wire may also have color by adding dye into the plastic material in the extrusion manufacturing process. However, the wire can only present monotonous and irregular color, but not sparkling and variety colors.
Currently, a thread winding method is utilized in manufacturing electrical wire. The method comprises winding a cotton thread or the like on the surface of stranded electrical wires to tie them together in a uniform shape, and extruding an opaque plastic material uniformly onto the surface of the wound electrical wires to form a uniform outer protection layer with better insulation. Such method is embodied in an apparatus as illustrated in FIG. 1. The apparatus comprises a machine frame 80 provided thereon a hollow rotation seat 13, a belt 16, and a drive device 81 together with the rotation seat 13 and belt 16 to form a chain drive. Further, an upright hollow shaft 14 is fixedly coupled to the center of the rotation seat 13. While the rotation seat 13 rotates as the drive device 81 activates the running of the belt 16, the hollow shaft 14 rotates simultaneously. Furthermore, the apparatus comprises a spool 15 having a hollow cylinder 153 as its rotation shaft and a rim 152 at either end, where thread 10 formed of cotton or the like is wound on the cylinder 153 between the rims 152.
As shown in FIG. 1, while winding the thread 10 on at least one wire 12, the process comprises the steps of putting the hollow cylinder 153 of the spool 15 onto the hollow shaft 14 with the rim 152 rested on the rotation seat 13, threading the wire 12 through the rotation seat 13 and the hollow shaft 14 from the bottom of the rotation seat 13, pulling the wire 12 from the above of the hollow shaft 14 to one or more cylinders of a take-up device 82, winding one end of the thread 10 around the wire 12 above the hollow shaft 14, and activating the drive device 81 and take-up device 82 for turning the spool 15 and keeping on pulling the wire 12. At this moment, the thread 10 is thereby unwound from the spool 15 due to the centrifugal force of rotation, and sequentially wound on the wire 12.
In view of the above, since the thread 10 is made of stranded cotton or other fiber, a predetermined tension and friction exist among the adjacent turns of the thread 10 wound on the spool 15 due to the interactive friction forces between the fibers thereof. When the spool 15 rotates, the thread 10 is unwound from the spool 15 due to the centrifugal force of rotation, and sequentially wound on the wire 12. At the same moment, the interactive friction forces between the fibers of the adjacent turns of the thread 10 enable the subsequent turns of the thread 10 still wound on the spool 15, without loosening from the spool 15. Therefore, the outer diameters of the hollow cylinder 151 from top to bottom can be the same in order for the thread 10 to be evenly wound on the cylinder 151 of the spool 15.
However, while winding fine thread with light weight on the wire by using the above winding method, the thread may become loosened due to no sufficient tension existing therein caused by air friction, which prohibits the thread from being tightly wound on the wire. Subsequently, the turns of thread wound thereon may become disengaged from the wire in a subsequent extrusion process due to the compression force of the extrusion. The disengaged turns of thread will be easily entangled together and may adversely affect the quality of forming a cable having a uniform outer layer. A solution to the above problem is proposed by putting a flywheel 27 on the hollow shaft 24 above the top of the spool 25, as illustrated in FIG. 2, wherein the flywheel 27 is formed of a bent steel rod and comprises a central hole 273, two arms 272 extended outward in opposite directions, and two eyes 271 each formed at the open end of the arm 272. While winding the fine thread 20 on the wire 22, the process further comprises the steps of threading the thread 20 through the eye 271 prior to winding the thread 20 on the wire 22, and activating the drive device and take-up device (both not shown) to rotate the spool 25 and thus the flywheel 27. The rotating speed of the flywheel 27 will be slightly higher than that of the spool 25, after a short period of time of operation, due to the inertia of the flywheel 27. At this moment, the flywheel 27 will apply a predetermined force (i.e., tension) on the thread 20 unwound from the spool 25 due to the centrifugal force of rotation. As a result, the unwound thread 20 is sequentially and tightly wound on the wire 22.
As to the strong thread with heavy weight, a relatively large tension is required to exert on the thread while winding the thread on the spool. As such, the thread tends to become tightly wound on the spool, resulting in increasing the interactive friction between the adjacent turns of thread. This may cause the thread difficult to be unwound from the spool for being subsequently wound on the wire in the manufacturing process. In a worse condition, the thread may break due to the large tension therein during winding, which will eventually impede the winding progress. A solution to the above problem is detailed in FIG. 3, wherein the spool 35 is configured to have a cone-shaped cylinder 351. A line from the top periphery to the bottom one of the cylinder 351 is at an angle of α with respect to a vertical line, which will make the diameter of the top end of the cylinder 351 smaller than that of the lower end. As contemplated, the unwound thread will go from a lower position of the cylinder having a larger diameter, as indicated by numeral 302, to a higher position of the cylinder having a smaller diameter, as indicated by numeral 301, prior to being wound on the wire 32 in the manufacturing process, which will suitably release the tension existing therein gradually. Thus, the thread unwound from the spool 35 may not become entangled with the adjacent turns. As a result, the thread will be more easily and smoothly wound on the wire 32.
Since the thread is made of stranded cotton or other fiber, the tension and friction existing among turns of the thread wound on the spool, due to the interactive friction between the fibers thereof, will prohibit the subsequent turns of the thread wound on the spool from loosening out of the spool while winding the thread on the wire. However, winding a flat, light, smooth and flexible tape 400, such as a color tape formed of Mylar coated with metal film, on the spool 45, as illustrated in FIG. 4 will cause the following problems because the interactive friction between the turns of tape 400 wound on the spool is completely different from that of the conventional thread:
(1) A predetermined tension must be applied on the tape 400 while winding the tape 400 on the spool 45, which will make the tape 400 being tightly wound on the spool 45. However, in utilizing any of the above prior arts in wrapping the tape 400 on the wire 42, the tension released by a turn of the tape 400 unwound from the spool 45 prior to being wrapped on the wire 42 may exert on the subsequent turns of the tape 401, 402, and 403. As such, the turns 401, 402, and 403 tend to disengage from the spool 45 due to little friction existing among them, and entangle together. The entangled turns 402 and 403 (see FIG. 4) will be subject to breakage while a pulling force is exerted thereon. This will apparently low down the performance of manufacturing high quality wire, especially in mass production.
(2) Typically, in order to permit the flywheel 47 to rotate freely, a tolerance F is provided between the hollow shaft 46 (after the flywheel 47 being put thereon) and a nut 43 secured on one end of the hollow shaft 46 above the flywheel 47, wherein a fixed distance H from the top of the nut 43 to the top of the rim 451 of the spool 45 is maintained. Such distance H will increase the angle β of the tape 400 at a section from the wire 42 to the eye 471 of the flywheel 47 with respect to the top surface of the flywheel 47. Thus, the tape 400 wrapped on the wire 42 may easily become not even and cause the subsequent turns of the tape 400 wrapped on the wire 42 wrinkled (48), as illustrated in FIG. 5, which will manufacture undesired cable with uneven surface.
(3) However, if the angle β of the tape 400 at a section from the wire 42 to the eye 471 of the flywheel 47 with respect to the flywheel 47 (i.e., wrapping angle) is too small, it may cause the lower edge of the tape 400 to rub the nut 43 and let the tape 400 be easily broken in a high speed operation, thus interrupting the manufacturing process.
(4) Finally, in an undesired condition, the tape 400 at a section from leaving the spool 45 to the eye 471 of the flywheel 47 may rub the edge of the rim 451 and let the tape 400 be easily broken in a high speed operation.
In this regard, it is inappropriate to utilize the conventional winding method to wrap the flat, light, smooth and flexible tape 400 on the wire 42 in a fast way to obtain a smooth and even surface wrapped on the wire 42. That is the reason why a variety of novel, colorful tape materials or tapes coated with metal film are still unable to be applied to the wire manufacturing. Thus, improvement exists in order to overcome the above drawbacks of prior art.